Dissertation / PhD Thesis

FZJ-2013-06691

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Aberrationskorrigierte Photoemissionsmikroskopie an magnetischen Systemen: Von statischer Charakterisierung zu zeitaufgelöster Abbildung

Nickel, F. (Corresponding author)FZJ*

2013
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-89336-913-3

Please use a persistent id in citations: http://hdl.handle.net/2128/5737

Abstract: This thesis aims at realizing time-resolved magnetic-imaging in an energy-filtered and aberration-corrected photoemission microscope (TRACX-PEEM). To routinely make use of higher lateral resolution in conjunction with improved transmission of the latest generation PEEM, the aberration coefficients C$_{3}$, C$_{c}$ of the electron lenses had to be measured experimentally. The phase space of the tetrode mirror-corrector was further on adapted to the determined lens aberrations in order to employ fully automatic and start-energy dependent aberration tracking. For efficient use of the synchrotron radiation a new time-resolving mode of operation was developed preserving energy-filtering and aberration-correction of the PEEM. The developments consist of a sample holder for excitation of a sample with a magnetic field up to 10 mT within 1 ns. Furthermore, a novel type of deflection gating was developed, to block the electron optical axis within a few nanoseconds. The system involves an electrostatic de ection electrode, as an additional electron-optical element, incorporated in a magnetic prism sector. The new operation mode enables time-resolved experiments using isolated bunches of the filling-pattern. To directly measure the excitation pulse during time-resolved experiments, a new method based on time- and spatially resolved secondary electron spectroscopy is developed. The method allows for quantifying the time-dependent secondary-electron spectra of a microstripline and further analysis of amplitude and shape of the excitation pulse. Within this thesis, magnetodynamic measurements using a novel type of aberrationcorrected PEEM were performed for the first time. The measurements were carried out on microstructured Permalloy samples. The magnetodynamic response of the latter was explored on the picosecond time-scale exploiting the newly developed TRACX-PEEM method. For additional survey and interpretation of the experiments, micromagnetic simulations were performed.

Keyword(s): Dissertation

Note: Universität Duisburg, Diss., 2013

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Contributing Institute(s):

1. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. 422 - Spin-based and quantum information (POF2-422) (POF2-422)

Appears in the scientific report 2013

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Database coverage:

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